CN110939422B - Horizontal well subsection multi-cluster current-limiting fracturing method with perforation sub-clusters - Google Patents
Horizontal well subsection multi-cluster current-limiting fracturing method with perforation sub-clusters Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 30
- 238000010276 construction Methods 0.000 claims abstract description 16
- 230000000694 effects Effects 0.000 claims abstract description 9
- 206010017076 Fracture Diseases 0.000 claims description 17
- 208000010392 Bone Fractures Diseases 0.000 claims description 9
- 230000000670 limiting effect Effects 0.000 claims description 7
- 239000011435 rock Substances 0.000 claims description 7
- 208000006670 Multiple fractures Diseases 0.000 claims description 5
- 230000000977 initiatory effect Effects 0.000 claims description 5
- 230000001360 synchronised effect Effects 0.000 claims description 4
- 238000005488 sandblasting Methods 0.000 claims description 3
- 230000009466 transformation Effects 0.000 abstract description 5
- 239000012530 fluid Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/11—Perforators; Permeators
- E21B43/114—Perforators using direct fluid action on the wall to be perforated, e.g. abrasive jets
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Abstract
The invention provides a horizontal well subsection multi-cluster current-limiting fracturing method with perforating sub-clusters, which comprises the following specific steps: determining the number of perforation clusters and the positions of the perforation clusters in a fracturing section; step two, arranging a plurality of perforating sub-clusters at each perforating cluster position, wherein the spacing between the perforating sub-clusters is not less than 2 m and not more than 8 m; thirdly, putting a perforating tool into the horizontal well section for perforating at a set position to form a perforating cluster with perforating sub-clusters; and fourthly, carrying out fracturing construction, wherein a plurality of sub-clusters of the perforation cluster can be cracked and tend to extend along different directions of two sides of the shaft, and hydraulic fractures which are approximately uniform and symmetrical on two sides of the shaft are formed at the positions of the perforation clusters in the section. According to the invention, by utilizing the current-limiting effect of the perforation holes, the cracks are initiated from the perforation sub-clusters and are respectively expanded to two sides of the horizontal shaft, so that the hydraulic cracks which are approximately uniform and symmetrical on two sides of the shaft are formed at the position of each perforation cluster. Therefore, the aims of reducing the generation of ineffective perforation clusters and improving the reservoir transformation degree can be achieved.
Description
Technical Field
The invention relates to a horizontal well subsection multi-cluster current-limiting fracturing method with perforating sub-clusters, and belongs to the field of oil gas and geothermal reservoir transformation.
Background
Horizontal well staged multi-cluster fracturing is a main means for developing compact oil-gas resources and hot dry rock geothermal resources at present. The method generally involves first setting a bridge plug to segment a horizontal wellbore and perforating at multiple locations on the casing in the segment using perforating guns, referred to as multiple clusters. Generally, each fracturing segment has 3-12 clusters of perforation holes, the cluster spacing is 10-30 m, and the length of each perforation cluster on the casing is 0.2-2 m. And then, pumping fracturing fluid into the segment in a large-displacement and large-liquid-volume mode so as to realize simultaneous fracture initiation and expansion of the hydraulic fracture from a plurality of perforation clusters. Although segmented multi-cluster fracturing can significantly reduce construction costs, the fracturing effect often cannot reach a desired level. The field productivity monitoring data shows that the distribution height of the staged multi-cluster fractured horizontal well productivity along the length direction of a shaft is non-uniform, and a plurality of perforation clusters even have no fluid output in the later production process. There were studies showing that the production of 2/3 came from a 1/3 perforation cluster, with a perforation cluster approaching 1/3 contributing nothing to the production capacity. The phenomenon is caused to a great extent by that strong stress interference exists among a plurality of synchronously-expanded cracks, so that only the cracks of a part of perforation clusters are successfully expanded outwards to form effective cracks, and the cracks of other perforation clusters are extruded and are difficult to extend outwards to form ineffective perforation clusters. In order to solve the problem, the industry generally adopts a current-limiting mode to limit fracturing fluid to continuously enter into dominant fractures and force the fracturing fluid to uniformly enter into each perforation cluster, so that the possibility of invalid perforation clusters in the staged multi-cluster fracturing process of the horizontal well is reduced, and a staged multi-cluster current-limiting fracturing technology of the horizontal well is formed.
The existing horizontal well subsection multi-cluster flow-limiting fracturing mainly has the following problems: because reservoir rock inevitably has heterogeneity of different degrees, under the supporting of stress interference effect among multiple fractures, horizontal well subsection multiple cluster flow-limiting fracturing is difficult to uniformly and symmetrically expand outwards as shown in figure 1. Under the effect of flow restriction, although each perforation cluster can successfully expand outwards, hydraulic fractures are difficult to simultaneously and fully expand outwards on two sides of a wellbore, and multiple fractures can alternately expand outwards on one side of the wellbore, as shown in fig. 2.
Therefore, the invention provides a horizontal well subsection multi-cluster flow-limiting fracturing method with perforating sub-clusters, which overcomes the defects of the prior art.
Disclosure of Invention
In order to overcome the defect that multiple cracks can be expanded outwards on one side of a shaft alternately in the prior art, the invention provides a horizontal well subsection multi-cluster current-limiting fracturing method with perforating sub-clusters.
The technical scheme adopted by the invention is as follows:
a horizontal well subsection multi-cluster flow-limiting fracturing method with perforation sub-clusters comprises the following specific steps:
determining the number of perforation clusters and the positions of the perforation clusters in a fracturing section;
step two, arranging a plurality of perforating sub-clusters at each perforating cluster position, wherein the spacing between the perforating sub-clusters is not less than 2 m and not more than 8 m;
thirdly, putting a perforating tool into the horizontal well section for perforating at a set position to form a perforating cluster with perforating sub-clusters;
step four, fracturing construction is carried out, construction discharge capacity is increased step by step in the fracturing process, under the influence of reservoir rock heterogeneity and the effect of perforation hole flow limiting, a plurality of sub-clusters of perforation clusters can crack and tend to extend along different directions of two sides of a shaft, and hydraulic cracks which are approximately uniform and symmetrical at two sides of the shaft are formed at the positions of the perforation clusters in the section;
and step five, repeating the step three and the step four until the fracturing operation of all fracturing sections of the horizontal well is completed.
In the second step, at least two perforating sub-clusters are arranged at each perforating cluster position, the interval between the perforating sub-clusters is not less than 2 m and not more than 8m, and the perforating parameters of the perforating sub-clusters are calculated and determined according to the throttling resistance required by synchronous fracture initiation and expansion of multiple fractures.
And the perforation parameters of the perforation sub-cluster comprise the number of the perforations and the diameter of the perforations.
The interval of the perforation sub-clusters is 3 m.
In the first step, the interval and the cluster interval of the staged multi-cluster fracturing of the horizontal well are determined through hydraulic fracturing analysis software, and the number of perforation clusters in the fracturing section and the positions of the perforation clusters are determined.
In the third step, the perforating tool is a shaped perforating gun.
In the third step, the perforating tool is hydraulic sand blasting.
Six perforating sub-clusters are arranged at each perforating cluster position, and the interval between every two perforating sub-clusters is 2-8 m.
The invention has the beneficial effects that:
the method is characterized in that perforation is carried out at a set position in a horizontal well section to form a perforation cluster with perforation sub-clusters, fracturing construction is carried out, construction discharge is increased step by step in the fracturing process, a plurality of sub-clusters of the perforation cluster are affected by heterogeneity of reservoir rocks and tend to extend along different directions of two sides of a shaft under the action of flow limiting effect of perforation holes, and hydraulic fractures with two sides of the shaft approximately symmetrical and uniform are formed at the positions of the perforation clusters in the section, so that the aim of improving the transformation degree of the reservoir is fulfilled.
The following will be further described with reference to the accompanying drawings.
Drawings
FIG. 1 is a schematic diagram of hydraulic fractures formed from an ideal flow-restricting fracture.
Fig. 2 is a schematic diagram of a hydraulic fracture which may be formed by a real flow-restricted fracture.
FIG. 3 is a schematic diagram of a horizontal well segmented multi-cluster flow-restricting fracturing perforation scheme with perforation sub-clusters.
FIG. 4 is a schematic diagram of hydraulic fractures formed by staged multi-cluster flow-restricting fracturing of a horizontal well with perforating sub-clusters.
Detailed Description
Example 1:
in order to overcome the problem that multiple cracks can be expanded outwards from one side of a shaft alternately in the prior art, the invention provides a horizontal well subsection multi-cluster current-limiting fracturing method with perforating sub-clusters as shown in figures 3 and 4.
A horizontal well subsection multi-cluster flow-limiting fracturing method with perforation sub-clusters comprises the following specific steps:
determining the number of perforation clusters and the positions of the perforation clusters in a fracturing section;
step two, arranging a plurality of perforating sub-clusters at each perforating cluster position, wherein the spacing between the perforating sub-clusters is not less than 2 m and not more than 8 m;
thirdly, putting a perforating tool into the horizontal well section for perforating at a set position to form a perforating cluster with perforating sub-clusters;
step four, fracturing construction is carried out, construction discharge capacity is increased step by step in the fracturing process, under the influence of reservoir rock heterogeneity and the effect of perforation hole flow limiting, a plurality of sub-clusters of perforation clusters can crack and tend to extend along different directions of two sides of a shaft, and hydraulic cracks which are approximately uniform and symmetrical at two sides of the shaft are formed at the positions of the perforation clusters in the section;
and step five, repeating the step three and the step four until the fracturing operation of all fracturing sections of the horizontal well is completed.
After fracturing is finished, the fracturing effect is evaluated according to fracturing microseism monitoring data and open flow oil testing results. The method is characterized in that at least 2 perforating sub-clusters are arranged at each perforating cluster position, and cracks are initiated from the perforating sub-clusters and are respectively expanded to two sides of a horizontal shaft by utilizing the current limiting effect of perforating holes, so that hydraulic cracks which are approximately uniformly and symmetrically formed on two sides of the shaft are formed at each perforating cluster position. The horizontal well subsection multi-cluster current-limiting fracturing method with the perforation sub-clusters can force hydraulic fractures of each perforation cluster to be approximately uniformly and symmetrically expanded on two sides of a horizontal shaft, so that the aims of reducing the generation of invalid perforation clusters and improving the transformation degree of a reservoir stratum can be fulfilled.
Example 2:
based on embodiment 1, in this embodiment, preferably, in the second step, at least two perforation sub-clusters are set at each perforation cluster position, the interval between the perforation sub-clusters is not less than 2 m and not more than 8m, and perforation parameters of the perforation sub-clusters are calculated and determined according to the throttling resistance required by the multiple fractures to achieve synchronous fracture initiation and expansion.
Preferably, the perforation parameters of the perforation sub-cluster comprise the number of holes and the diameter of the holes.
Preferably, the interval of the perforation sub-cluster is 3 m.
Preferably, in the first step, the interval and the cluster interval of the staged multi-cluster fracturing of the horizontal well are determined through hydraulic fracturing analysis software, and the number of perforation clusters and the positions of the perforation clusters in the fracturing section are determined.
Preferably, in the third step, the perforation tool is a shaped perforating gun.
Preferably, in the third step, the perforation tool is hydraulically sand-blasted.
Preferably, six perforating sub-clusters are arranged at each perforating cluster position, and the interval between every two perforating sub-clusters is 2-8 m.
The method comprises the following specific operation steps:
firstly, determining construction parameters of interval, cluster interval, discharge capacity, fracturing fluid viscosity and sand ratio of horizontal well segmented multi-cluster fracturing by adopting hydraulic fracturing analysis software (such as StimPlan and FracProPT);
secondly, perforating the optimized perforation clusters by adopting a shaped perforating gun or a hydraulic sand blasting process to form perforation clusters with perforation sub-clusters, wherein as shown in figure 3, each perforation cluster position is provided with not less than 2 perforation sub-clusters, the interval between the perforation sub-clusters is not less than 2 m and not more than 8m, and perforation parameters of the perforation sub-clusters are calculated and determined according to throttling resistance required by synchronous fracture initiation and expansion of multiple cracks in a section;
thirdly, performing segmented multi-cluster flow-limiting fracturing construction by adopting the obtained construction parameters, and forming hydraulic fractures shown in the figure 4 in each fracturing segment;
fourthly, repeating the steps for construction to complete all fracturing well sections of the operation well;
and fifthly, evaluating the fracturing effect according to the fracturing microseism monitoring data and the open flow oil testing result.
The method is characterized in that perforation is carried out at a set position in a horizontal well section to form a perforation cluster with perforation sub-clusters, fracturing construction is carried out, construction discharge is increased step by step in the fracturing process, a plurality of sub-clusters of the perforation cluster are affected by heterogeneity of reservoir rocks and tend to extend along different directions of two sides of a shaft under the action of flow limiting effect of perforation holes, and hydraulic fractures with two sides of the shaft approximately symmetrical and uniform are formed at the positions of the perforation clusters in the section, so that the aim of improving the transformation degree of the reservoir is fulfilled.
The above examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention, which is intended to be covered by the claims and any design similar or equivalent to the scope of the invention. The method steps and software parameter calculation are well known and commonly used in the industry, and are not described in detail herein.
Claims (6)
1. A horizontal well subsection multi-cluster current-limiting fracturing method with perforation sub-clusters is characterized in that: the method comprises the following specific steps:
determining the number of perforation clusters and the positions of the perforation clusters in a fracturing section;
step two, arranging a plurality of perforating sub-clusters at each perforating cluster position, wherein the spacing between the perforating sub-clusters is not less than 2 m and not more than 8 m; the perforation parameters of the perforation sub-clusters are calculated and determined according to the throttling resistance required by synchronous fracture initiation and expansion of multiple fractures;
thirdly, putting a perforating tool into the horizontal well section for perforating at a set position to form a perforating cluster with perforating sub-clusters; the perforation tool is hydraulic sand blasting or a perforation gun;
step four, fracturing construction is carried out, construction discharge capacity is increased step by step in the fracturing process, under the influence of reservoir rock heterogeneity and the effect of perforation hole flow limiting, a plurality of sub-clusters of perforation clusters can crack and tend to extend along different directions of two sides of a shaft, and hydraulic cracks which are approximately uniform and symmetrical at two sides of the shaft are formed at the positions of the perforation clusters in the section;
and step five, repeating the step three and the step four until the fracturing operation of all fracturing sections of the horizontal well is completed.
2. The horizontal well subsection multi-cluster flow-limiting fracturing method with perforation sub-clusters is characterized in that: and the perforation parameters of the perforation sub-cluster comprise the number of the perforations and the diameter of the perforations.
3. The horizontal well subsection multi-cluster flow-limiting fracturing method with perforation sub-clusters is characterized in that: the interval of the perforation sub-clusters is 3 m.
4. The horizontal well subsection multi-cluster flow-limiting fracturing method with perforation sub-clusters is characterized in that: in the first step, the interval and the cluster interval of the staged multi-cluster fracturing of the horizontal well are determined through hydraulic fracturing analysis software, and the number of perforation clusters in the fracturing section and the positions of the perforation clusters are determined.
5. The horizontal well subsection multi-cluster flow-limiting fracturing method with perforation sub-clusters is characterized in that: in the third step, the perforating gun is a shaped perforating gun.
6. The horizontal well subsection multi-cluster flow-limiting fracturing method with perforation sub-clusters is characterized in that: six perforating sub-clusters are arranged at each perforating cluster position, and the interval between every two perforating sub-clusters is 2-8 m.
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|---|---|---|---|---|
| US8281860B2 (en) * | 2006-08-25 | 2012-10-09 | Schlumberger Technology Corporation | Method and system for treating a subterranean formation |
| WO2016011327A2 (en) * | 2014-07-17 | 2016-01-21 | Schlumberger Canada Limited | Heel to toe fracturing and re-fracturing method |
| CN105370259A (en) * | 2014-08-29 | 2016-03-02 | 中国石油化工股份有限公司 | Staged fracturing method of horizontal well |
| CN108561106A (en) * | 2018-03-12 | 2018-09-21 | 中国石油天然气股份有限公司 | Oil and gas exploitation method for increasing recovery ratio by controlling reserves through artificial seams |
| CN109933860A (en) * | 2019-02-25 | 2019-06-25 | 北京科技大学 | Shale gas pressure break horizontal well cluster spacing optimization method |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8281860B2 (en) * | 2006-08-25 | 2012-10-09 | Schlumberger Technology Corporation | Method and system for treating a subterranean formation |
| WO2016011327A2 (en) * | 2014-07-17 | 2016-01-21 | Schlumberger Canada Limited | Heel to toe fracturing and re-fracturing method |
| CN105370259A (en) * | 2014-08-29 | 2016-03-02 | 中国石油化工股份有限公司 | Staged fracturing method of horizontal well |
| CN108561106A (en) * | 2018-03-12 | 2018-09-21 | 中国石油天然气股份有限公司 | Oil and gas exploitation method for increasing recovery ratio by controlling reserves through artificial seams |
| CN109933860A (en) * | 2019-02-25 | 2019-06-25 | 北京科技大学 | Shale gas pressure break horizontal well cluster spacing optimization method |
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